If the OP is happy with whatever compound he finally chooses, the choke will undoubtedly sound sublime!
Ok I've decided after weighing the pros and cons of many materials in terms application messiness, convenience, need to heat, need to vibrate, etc. And weighing the fact that I don't want rock hard, I want something flexible yet rigid. And weighing disqualifiers like the low melting point of wax or the jello-like weakness of silicone RTV. I'm going with a urethane compound specifically made for potting. The durometer rating of around 90A I like best, this is about the hardness of urethane skateboard or roller blade wheels, dense, rigid, yet with some give, it cures in 24 hours, no heat, no stress. Thanks NareshBrd for the links to suppliers, thanks Brinkman for first mentioning urethane. It comes in single use pre measured packets or bottled. Everyone has been helpful and constructive. And yes I have heard noisy choke input chokes, its annoying. Getting something from this page most likely: The premeasured packets are attractive if I can get the quantity nailed to pour two chokes.
https://www.newark.com/w/c/chemicals-adhesives/potting-compounds?potting-compound-type=pur-polyurethane-&range=inc-in-stock|not-exc-nic&st=Potting+Compounds&pageSize=25
https://www.newark.com/w/c/chemicals-adhesives/potting-compounds?potting-compound-type=pur-polyurethane-&range=inc-in-stock|not-exc-nic&st=Potting+Compounds&pageSize=25
Looks good. I like like everything about it except the price. Please update this thread with pictures (if possible) as your project progresses.
If you are worried about transformer noise then you might want to mount the mains transformer flat on the chassis and use some silicon anti-vibration grommets. AirTight does it and I've just done it on my last build, no more mechanical hum from the chassis when the amplifier is switched on.
(I bought some new bell covers in order to change a Hammond mains transformer to flat mounting, had to carefully route some wires to the other side. Don't forget to make sure to seperately earth the transformer, just in case.)
(I bought some new bell covers in order to change a Hammond mains transformer to flat mounting, had to carefully route some wires to the other side. Don't forget to make sure to seperately earth the transformer, just in case.)
Thanks EL506 I'm using a toroid so it will already be sitting on a 3mm sheet of neoprene but it can't hurt to use two sheets under it. That won't be potted, this thread pertains to potting the choke-input choke. For this potting project I did have to order some nicer transformer cans, the enclosures I was going to make didn't look very good. But those won't arrive for 4 weeks. When I get them I'm hoping to video the pour and how it looks after its cured.
Did not read the whole thread. But if you are using a choke input then that choke can be noisy too and the same principle applies. FWIW some of the higher end Philips valve radios had their transformers vertically mounted on a rubber grommets, unfortunately the Hammond bell covers' feet are too thin for that.